Inertia type brake control means



Nov. 26, 1940. J. C. MccUNE 2,223,114

INERTIA TYPE BRAKE 'CONTROL MEANS Nov. 26, 1940. J. c. MccuNE INERTIA TYPE BRAKE CONTROL MEANS Filed Feb. l0, 1939 ll Sheets-Sheetl 2 INVENTOR JOSEPH cMccuNE BY ATTORNEY Nov. 26, 1940. J. c. MccuNE INERTIA TYPE BRAKE CONTROL MEANS Filed Feb. 10, 1959 11 Sheets-Sheet 3 Wm, wm,

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ATTORNEY Nov. 26, 1940. .1. c. MccUNE INERTIA TYPE BRAKE CONTROL MEANS Filed Feb. l0, 1959 ll Sheets-Sme?l 4 lNvENToR JOSEPH C. MQCUNE ATTORNEY J. c. MccuNE 2,223,114

Nov. 26, 1940.

INERTIA TYPE BRAKE CONTROL MEANS 10, 1939 ll SheetsSheet 5 Filed Feb.

MIMI' BY l MM'M

`MTORNEY Nov. Z6, 1940.

J. C; MCCUNE INERTIA TYPE BRAKE CONTROL MEANS Filed Feb. lO, 1939 11 Sheets-Sheet 6 INVENTOR vJOSEPH CMCCUNE 9' im' ATTORNEY Nov. 26, 1940. J. c. MccuNE INER-'I'I-A TYPE BRAKE CONTROL MEANS Filed Feb. l0, 1939 1l Sheets-Sheet 7 INVENTOR JOSEPH C. McCUNE n l .M ArroRNEY rl n A f l l if Nov. 26, 1940. J. c. MccuNE INERTIA TYPE BRAKE CONTROL MEANS Filed Feb. `l0, 1939 11 SheeCs--SheefI 8 INVENTOR msm 4 9 H., n mm. 3 m 2 Q LM 2. EN Il BN 2 ll: .I|N\ m n EN N n n ANNIIHM. www. 6N .u\.\ 7//V////// 08N m 444/44 4444444 4444444444444fN u L 9 .E m m N w U c O, m 1 M m w B F c m d J. N .M n F l i i, M V l E m 4 .N` @93N n l S SN ulANm In* I n w `N TWN l www v ,mmm 6, ad I www* 2 I .3m M n* TTbRNEY N. l? L.. MQ.N\ J .mmfN mmm III www fr mom QN .,.i l.. .www Y om QN N www .WNW ne mwN www .a f am@ J r www vom, L

NV- 26, 1940- J. c, MocuNE 2,223,114

l INBRTIA TYPE BRAKE CONTROL MEANS Filed Feb. 1o, 1939 11 sheets-sheet 1o INVENTOR 05E FH QMQUNE ATTORNEY NOV. 26, 1940. J. C, McCUNE 2,223,114

INERTIA TYPE BRAKE CONTROL MEANS Filed Feb. l0, 1939 1l Sheets-Sheet ll NVENTOR JOSEPH C. MCCUN A'TTORNE'Y Patented Nov. 26, 1940 UNITED STATES PATENT OFFICE INERTIA TYPE BRAKE CONTROL MEANS Application February 1li, 1939. Serial No. 255,649

This invention relates to inertia type brake control means and has particular relation to rotary inertia devices responsive to the rate of rotative acceleration or deceleration of an individual vehicle wheel or wheel axle for controlling the vehicle brakes.

With the advent of modern railway trains intended to travel normally at speeds in excess of one hundred miles per hour, it has become increasingly necessary to provide braking equipment wherein `the rubbing parts of the brake devices may absorb the kinetic energy of the train without undue heating and wear or failure. One of the more recently proposed types of brakes for trains traveling normally at high speeds in excess of one hundred miles per hour is of the disc type. One such type of disc brake is disclosed and claimed in my copending application Serial No. 225,785, filed August 19, 1938, and comprises briey a plurality of alternately disposed rotative and non-rotative discs or rings, the non-rotative discs being mounted in the vehicle wheel truck in a manner so as not to rotate and the rotative discs being arranged to rotate with the vehicle wheel of an individual wheel and axle assembly. The non-rotative and rotative discs are arranged in two groups spaced from each other and, interposed between the two groups, are a plurality of brake cylinders circularly arranged in concentric relation to the axle of an individual wheel and axle assembly. Each brake cylinder is provided with two pistons movable in opposite directions to eiect frictional engagement of the non-rotative and the rotative discs in the two groups.

It is an object of my invention to provide a brake control means of the rotary inertia type adapted to be embodied within and suited to a disc brake of the type described in my copending 40 application Serial No. 225,785, referred to above.

In the case of a rotary inertia device having an inertia ring mechanically associated with the vehicle wheels, it is inevitable that the continued road shock on the wheels result in corresponding shock and stress on the parts of the rotary inertia device and possibly even undesired accidental operation thereof. It is accordingly another object of my invention to provide a rotary inertia device adapted to be mechanically associated with the vehicle wheels and including some means for cushioning the eiect of road shock on the inertia device.

In a rotary inertia device adapted to successively close a series of switches according to the rate of acceleration or deceleration, it is impera- (Cl. 20o-52) tive that the rotary inertia device be rendered inoperative immediately in the event of failure of the device to properly respond to the rate of acceleration or deceleration, as due to breaking of the usual resilient means yieldingly resisting 5 movement of the inertia ring of the inertia device according to the degree of inertia force exerted thereon. It is accordingly another object of my invention to provide a rotary inertia device of novel construction adapted to automatically render all of the electrical circuitscontrolled by inertia device inoperative upon failure of the inertia device to properly respond to the rate of acceleration or deceleration of the train.

It is another object of my invention to provide a rotary inertia device of novel construction adapted to be associated with an individually rotatable vehicle wheel.

The above objects and other objects of my invention which will be made apparent hereinafter, are attained by several embodiments of my invention subsequently to be described and shown in the accompanying drawings wherein Fig. 1 is a plan view, partly in section, of a wheel and axle assembly showing in simpliiled form a disc brake device and a rotary inertia. device constructed and arranged therein according to my invention,

Fig. 2 is an enlarged sectional view taken on the line 2-2 of Fig. i showing, in detail, the construction of the rotary inertia device,

Figs. 3, 4 and 5 are sectional views taken on the lines 3 3, 4 4 and 5-5 respectively of Fig. 2, showing further details of construction of the rotary inertia device, 35

Fig. 6 is a partial plan view taken substantially on the line 6-6 o'f Fig. 2, showing in further detail the construction of the rotary inertia device,

Fig. 7 is a diagrammatic simpliiied view, showing the electric circuit connections within the rotary inertia device itself and the collector ring arrangement whereby electrical connections are made to the rotating parts of the device,

Fig. 8 is an enlarged sectional view taken substantially on the line 8 8 of Fig. 1, showing the plurality of brake cylinders circularly disposed in concentric relation to the axle of a wheel and axle assembly,

Fig. 9 is a fragmentary view, showing a detail of the end cover shown in Fig. 8,

Fig. 10 is an enlarged sectional view taken substantially on the line Il-Ill of Fig. 1 and exactly on the line lI-IU of hereinafter referred v to Fig. 12, showing the manner of mounting the collector rings and associated brush holder.

Fig. 11 is a. plan view of a part of the brush holder shown in Fig. 10, showing the arrangement of the brushes therein.'

Fig. 12 is a sectional view taken on the line I2`|2 of Fig. 10 showing further details of construction.

Fig. 13 is an enlarged sectional view showing a second embodiment of a rotary inertia device adapted especially for use in connection with a disc brake device of the type shown in my copending application Serial No. 225,785 referred to above.

Fig. 14 is a sectional view taken on the line I4-I4 of Fig. 13 showing further details-of construction of the embodiment shown in Fig. 13,

Fig. `15 is a sectional view, partly diagrammatic in form, showing internal electrical connections within the rotary inertia device of Figs. 13 and 14, and

Fig. 16 is a sectional View taken on the line lI--I6 of Fig. 13, showing further details of construction of the embodiment shown in Fig. 13,

Fig. 17 is a vertical sectional view, showing a third embodiment of rotary inertia device adapted particularly for operation in connection with an individually rotatable vehicle wheel, and

Fig. 18 is a sectional view taken on the line I8--I8 of Fig. 17 showing in further detail the arrangement of parts and construction of the rotary inertia device shown in Fig. 17.

DEscarPrroN 0F EMBODIMENT SHOWN IN .FIGUuEs 1 'ro 12 The rst embodiment of my invention is shown in Figs. 1 to 12 inclusive of the accompanying drawings. Referring to Fig. 1, there is shown a Wheel and axle assembly comprising a pair of vehicle wheels I I secured at opposite ends respectively of a hollow tubular axle I2, as by a press fit, the two wheels being adapted to roll on opposite rails I3 of a railway track. The wheels Il are rotatably mounted on a solid axle Il which extends through the tubular axle |2 and projects beyond the outer face of each of the wheels II into journals suitably mounted and arranged in a wheel truck. The tubular axle |2fis provided at y opposite ends with flanges or hubs of larger diameter than the central portion, and roller bearings I5 are disposed between bearing rings i6 and l1 secured, respectively, within the hubs of the tubular axle and in surrounding relation to the solid axle I4, to mount the wheels and the connecting tubular axle I2 for rotation in concentric relation to the solid axle I4.

A cover plate I8 having a central opening through lwhich the solid axle Il extends is secured, as by screws I3, to the outer face of the hub portion of the vehicle wheels II for holding the bearing rings I6 and in position and adjusting the clearance of the roller bearings I5 between -the bearing rings I8 and I1. The wheels I and the connecting tubular axle I2 thus rotate independently of rotation of the solid axle |4, although as a matter of fact, the axle I4 may rotate by virtue of the rotatable mounting thereof at opposite ends if suitably journaled as previously indicated.

Associated with the wheel and axle assembly, including wheels II, is a disc brake of the type shown and described in detail in my above-referred to copending application Serial No. 225,785. Since the disc brake per se is not a part of my present invention, the parts of the brake are shown in simplified form but it should be understood that the brake device is intended actually to be of the form and construction shown in my copending application Serial No. 225,785.

Briefly, the disc brake apparatus shown in Fig. 1 comprises a supporting rectangular frame-work including side truss members 2| having suitable Journals 22 midway of the opposite ends thereof whereby the truss members 2| are rockably supported on the outer surface of the tubular axle l2. The two truss members 2| are disposed in spaced relation with respect to each other along the tubular axle I2 and their corresponding (ends on each side of the axle I2 are connected by a circular rod or shaft 23 preferably, as shown in Fig.A

8, of tubular construction to reduce the weight thereof.

'I'he truss members 2| are formed in two pieces adapted to be secured together at different points along the length thereof, as by suitable bolts 24 (see Fig. 12), the end portions being adapted to provide a suitable hub in which the ends of the connecting shaft 23 are clamped securely.

Each of the truss members 2| is provided at the hub portion thereof with a bushing or bearing ring 25 (Fig. 10) which in turn surrounds and engages in a suitable peripheral groove or recess in a sleeve 26 fixed to the axle I2. Sleeve 26 is formed in two complementary portions disposed around the outside surface of the tubular axle I2 and secured together in clamping relation to the axle as by a plurality of securing bolts and nuts 2l.

The sleeve members 26 are, furthermore, securely fixed to the tubular axle I2 by means of suitable screws 28.

The rectangular supporting frame-work including the truss members 2| is held against rotation by a suitable connection with the wheel truck. As indicated, this may be accomplished by providing an end member 23 on the rectangular frame that extends into the recess of a yoke 30 attached to a xed part of the wheel truck, such as the transverse strut or transom 40.

Each of the sleeve members 26 has a pair of circular radially extending flanges 23 and 3| formed by the cooperation of the two portions of each sleeve member, the flange 29 being at th inner end of the sleeve and the flange 3| at the outer end of the sleeve. The sleeve member 26 on which the right-hand truss member 2| in 1 is rockably supported is longer than the other sleeve member 26 so as to provide a greater distance between the two flanges 23 and 3| thereon for a purpose which will be hereinafter made apparent.

A plurality of rods or shafts 33, specifically illustrated as four in number, (see Fig. 8) are provided for connecting the radial iianges 29 of the two sleeve members 23. the rods 33 being disposed in substantially equally spaced relation to each other and in parallel relation to the tubular axle I2. The ends of the rods 33 are secured to the flanges 29 as by suitable nuts 3l screwed on the threaded outer ends of the rods 33.

To the inner face of each of the radial flanges 25 on the sleeve members 23 is secured, as by bolts 36, a braking element 35 in the form'of a ring of suitable material such as cast iron.

There is alsoprovided in associated relation with each of the flanges 25 a pair of 'brake elements 31 and 33 in the form of rings of suitable material, the rings 31 and 33 being disposed in concentric relation to the tubular axle I2 and in spaced axial relation with respect to each other and the corresponding flange 23. The rods 33,

joining the two iianges 29, extend through close fitting openings in the brake rings 31 and 35, lthereby slidably mounting the rings. The three brake rings 35, 31 and 39 associated with the flange 29 of each of the sleeve members 29 are thus adapted to rotate with the vehicle wheels at all times.

A set of so-called non-rotative brake rings 4|, 42 and 43 is provided for each set of rotative rings 35, 31 and 38, the brake rings 4|, 42 and 43 being disposed in concentric relation to the tubular axle l2 in alternate arrangement with the rotative rings. More specifically the inner areal of each ring 4| is interposed between the rotative brake rings 35 and 31, the inner area of ring 42 is interposed between the rotative rings 31 and 39, and the ring 43 is disposed on the opposite side of the rotative brake ring 38 to the ring 42.

The brake rings 4|, 42 and 43 are provided with suitable openings at diametrically opposite points therein through which the shafts 23, connecting the side trusses 2| of the rectangular frame-work, extend in supporting relation.

Interposed between the two innermost non-rotative brake rings 43 is a brake cylinder housing 45, shown in detail in Fig. 8. As will be seen clearly in Fig. 8, the brake cylinder housing 45 is formed in two complementary portions and is suitably provided at the opposite ends thereof with journal portions for supporting the housing at opposite ends on the shafts 23 of the rectangular frame-work. 'Ihe two portions of the housing 45 are secured together as by a plurality of bolts 41 at each of the iournals at the opposite ends thereof.

As will be further evident in Fig. 8, the brake cylinder housing is generally annular in character and surrounds the tubular axle l2 in concentric relation. Each portion of the brakev cylinder housing 45 has formed therein a plurality of brake cylinders 49 so spaced with respect to each other that when the two portions of the housing are assembled all of the brake cylinders are in substantially equally spaced relation with respect to each other. Obviously, the number of the brake cylinders l49 may be varied as desired, eight brake cylinders being shown specifically merely for purposes of illustration.

As described in detail in my copending application Serial No. 225,785, referred to above, each of the brake cylinders 49 contains two oppositely moving pistons arranged to have fluid under pressure admitted therebetween by suitable control means, each of the pistons being adapted to exert a force on the corresponding brake ring 43 so as to shift it along the tubular axle |2 and thereby cause all of the rotative brake rings 35, 31 and 38 and non-rotative brake rings 4|, 42 and 43 to frictionally engage one another. With the rotative and non-rotative brake rings in frictional engagement with one another, the rec- `tangular frame-work has a torque exerted thereon tending to cause rotation thereof with the vehicle wheels. The rectangular frame-work is, however, held against more than a slight limited amount of movement with respect to the wheel truck by the previously described connection with the transverse member or transom of the wheel truck.

When the fluid under pressure is released from between the brake cylinder pistons, the brake rings are automatically restored to the normal separated positions thereof, as shown in Fig. 1, by the various release springs which are sufficiently obvious in character and operation from the drawings as to necessitate -no description thereof herein.

In order to conserve space as well as to provide a compact arrangement of parts, I propose to utilize the space within the circular opening 4l in the brake cylinder housing to contain a rotary inertia device adapted to operate in response to and register rates of acceleration and deceleration of the vehicle wheels Il. Referring toFigs.2,3.4and5.itwillbeseenthat the rotary inertia device comprises an inertia element or ring 5| that is rotatively mounted on the tubular axle I2 in a manner to be presently described. Inertia ring 5| has a relatively thin radially extending web 52, a relatively wide and thick outer rim or flange 53 and an inner flange 54 hereinafter referred to as the hub through which the tubular axle |2 extends.

A split ring member 55 is secured in concentric relation around the outer surface of the tubularg axle I2 with an intervening cushioning ring 55 of resilient yieldable material, such as rubber, the purpose of which is to minimize the effect of road shock on the parts of the rotary inertia device. The hub 54 and the ring member 55 are provided with complementary substantially V- shaped peripheral grooves 51 and 59 respectively andthe hub 54 of the inertia ring 5| so closely surrounds the ring member 55 as to confine a plurality of ball bearings 59 in the peripheral grooves, thereby constituting a substantially frictionless rotative mounting of the inertia ring 5| which serves at the same time to secure the.

inertia ring for rotation in a fixed place with respect to the tubular axle I2. The ball bearings 59 are held in fixed substantially equally spaced relation around the periphery of the ring member 55 by a plurality of spacers 9|. The spacers 6| are in the form of short arcuate straps having at opposite ends thereof, circular openings large enough to accommodate the ball bearings 59, and midway of the ends a transversely extending portion or lug through which extends a screw 52 for securing the spacer to the ring member 55, each spacer accordingly holding two ball bearings in position, (see Fig. 5). It will be understood that the spacers 5| are of a thickness less than the clearance between the hub 54 and the n'ng 55 so as not to interfere with the free rotative movement of the inertia ring 5|.

As a practical matter, the inertia ring 5| and the ring member 55 each comprise two similar and complementary half-portions adapted to be secured together after assembly around the tubular axle |2.

In order to insure true circularity of the inertia ring 5| and the ring member 55 they are both initially formed as a complete ring, all necessary machining operations being completed including the formation of the peripheral grooves 51 and 59 while the inertia ring and ring member are in integral form.- When the machining operations on the inertia ring 5| are completed, suitable tapped holes are formed in the inner surface of the outer flange 53 of the inertia ring for receiving the securing bolts 55 of peripheral tie plate members 66 that are symmetrically disposed with respect to the intended diametrical line of severance of the inertia ring. It will be apparent that four of the tie plates 65 are provided, two on each side of the radial web 52 at one point in the periphery of the inertia ring and two on opposite sides respectively of the web 52 at a point diametrically opposite to the rst two.

In a similar manner, prior to the severance of the inertia ring 5| into two portions, holes are suitably located in the web 52 of the inertia ring in symmetrical relation on opposite sides of the intended line of severance of the inertia ring for receiving securing bolts 6l for additional tie plates 61. It will be apparent that there are four of the tie plates 61, two on opposite sides of the web 52 at one point adjacent the hub 54 of the inertia ring and two on opposite sides respectively of the web 52 at a point diametrically opposite the first two.

'I'he rods 33 connecting the radial flanges 29 of the sleeve members 26 extend through the space between the tubular axle I2 and wall of the brake cylinder housing 45 forming the circular opening 48. In order to provide an inertia ring 5| of as large a diameter as possible, without interference with the rods 33, it is necessary to cut recesses 69 in the rim 53 of the inertia ring 5I to enable the rods 33 to extend therethrough, the recesses 69 being of such size as to provide adequate clearance for the limited movement of the inertia ring 5| rotatively with respect to the tubular axle I2 that is permitted. Such recesses 69 weaken the rim 53 of the inertia ring and therefore two of the recesses 69 are located symmetrically with respect to the intended line of severance of the inertia ring 5| so that the tie plate 66 may act as reinforcing elements as well as elements for tieing the two portions of the inertia ring together.

In order to reinforce the rim 53 at the remaining recesses 69, additional reinforcing or tie plates 66 are provided, suitable holes being provided in the rim 53 of the inertia ring, for receiving the securing bolts 65 for the tie plates, prior to the severance of the inertia ring 5|.

If desired, the tie plates 66 may be secured in position prior to the cutting of the recesses 69 since the recesses 69 extend into the tie plates 66, thereby enabling the portions of the recess 69 in the tie plates' 66 to be cut at the same time that the portion of the recess 69 in the rim 53 and web 52 is cut. After the recesses 69 are cut, the tie plates 66 and 61V may then be removed and the inertia ring 5I cut into two half-portions along the diametrical line of severance. It will thus be seen that when the inertia ring 5I is reassembled in concentric relation to the tubular axle I2, it has a true circular form notwithstanding the portion of material removed during the process of severing the inertia ring 5| into two portions.

In a similar manner, the ring member 55 is machined on the inside and outside surfaces thereof and the peripheral groove 51 formed therein. Then, after locating the intended diametrical line of severance of the ring member 55 into two portions, tie strapsr 13 are clamped in position and suitable threaded bores and smooth bores are formed in the straps and ring member 55 for receiving screws 1| and dowel pins 12 respectively that secure opposite ends of the tie straps 13 to the two portions of the ring member 55. It will be seen (Fig. 4) that four tie I ring member 55, the tie straps 13 are removed and the ringsevered by cutting along the intended diametrical line of severance. It will accordingly be seen that when the ring member 55 is assembled in concentric relation around the tubular axle I2 the true circular form thereof is assured.

'I'he rubber cushioning ring 56 is made in the form of a single strip that is bent around the tubular axle I2 so as to cause the two opposite ends thereof to abut each other in adjacent relation, the rubber ring 56 being manually held in position while the ring member 55 is being assembled on the tubular axle I2.

Obviously, the brake cylinder housing 45 may be assembled in concentric relation to the inertia ring 5| after the inertia ring 5| is mounted on the tubular axle I2. In the event of possible repairs to the rotary inertia device, access thereto may be had under service conditions merely by unscrewing the bolts 41 securing the two hub portions of the brake cylinder housing 45 together and removing the brake cylinder housing.

After the ring member 55 is assembled on the tubular axle I2, the ball bearing spacers 6| are secured in position. The ball bearings are then placed in two of the spacers on the top side of the axle and one half-portion of the inertia ring 5| placed over the corresponding portion of the ring member 55. The wheels and the tubular axle are then rotated through one hundred eighty degrees while holding the half-portion of the inertia ring in place and the ball bearings then inserted in the remaining spacers 6| now on the top side of the axle. The other half of the inertia ring is then placed in position and the two portions of the inertia ring secured top gether by means of the tie plates 66 and 61.

With the ring member 55 fixed on the tubular axle, the inertia ring 5| is interlocked therewith by the ball bearings 59 and held against movement along the tubular axle I2 for rotation in a xed plane between the vehicle wheels I I.

The web 52 of the inertia ring 5| has two openings 15 cut therein at diametrically opposite points, the openings extending from the hub 54 to the outer rim 53. The openings 15 are of substantially the same size so as not to disturb the dynamic or static balance of the inertia ring.

One ofthe openings 15 is adapted to receive a contact switch mechanism 16 and the other opening 15 is adapted to receive a bumper arrangement for limiting the degree of relative rotative movement between the inertia ring 5I and the ring member 55 secured to the tubular axle I2.

Thel contact switch mechanism includes a leaf spring 18 that is relatively wide at one end and tapered to a relatively narrow width at the opposite end, as shown in Fig. 3. The leaf spring 18 is disposed between and clamped along the wide end thereof between two separate blocks 19, of insulating material preferably of molded character, by two through bolts 82, the insulating blocks 19 and the Wide end of the leaf spring 18 being provided with a suitable recess or groove 83 enabling the insulating blocks 19 to straddle the hub 54 of the inertia ring with clearance and to be secured to the ring member 55 on opposite sides of the web 52 of the inertia ring as by suitable bolts or screws 84 (see Fig. 6).

When so secured to the ring member 55, theY leaf spring 18 extends radially outward within the opening 15 to a point approaching the inner surface of the rim 53 of the inertia ring 5I where the outer end is held securely and firmly between allgned knife edges formed on lugs 86 of insulating material that are secured by screws 91 to the inner surface of the rim 59 of the inertia ring 5|.

It will thus be seen that the leaf spring 1. yieldingly resists rotative movement of the in- 5 ertia ring 5| with respect to the ring member 15 and tubular axle |2 in either direction.

I'he provision of a radially oriented leaf spring has certain advantages over other types of resilient drive connections adapted to perform a similar function, in that the force of opposition which it exerts to resist relative movement between the inertia ring and axle is not subject to possible variation, during rotation of the axle, caused by centrifugal forces. It will be seen that since the centrifugal forces are exerted radially they do not aect the lateral bending strength of the spring.

The leai spring 19 is provided on each side and adjacent the outer end thereof with a row 20 of three contact tips n ef any suitable materiel, such as silver. The contact tips on opposite sides of the leaf spring are in alignment and may be secured to the leaf spring as by spot welding each corresponding pair of contact tips together through a small opening in the leaf spring.

As seen especially well in Fig. 6, each of the insulating blocks 19 is provided with three adjacent parallel slots or recesses 99 open on the side engaging the leaf spring 19, and in each of the grooves 99 is received a contact finger in the form of a bell crank, the contact fingers on one side of the leaf spring 19 being identified by the reference numerals 9|, 92 and 93 respectively and the corresponding contact fingers on the opposite side ef the leef spring 1s being identified by the reference numerals 9Ia, 92a and 93a respectively.

Each set of the contact fingers is pivoted at the fulcrum thereof on a steel pin 95 that extends transversely through the corresponding insulating block 19 and is held in position by spring collars 96 at opposite ends thereof that are adapted to snap into suitable peripheral grooves g at the ends of the pin 95. Each of the contact 4 fingers is provided with a bushing 91 of insulated material to insulate the contact fingers from the steel pin 95 and from each other. Each of the contact fingers has a relatively long arm 99 and a relatively short arm 99 as shown in Fig. 2, the llong arm 99 extending radially outward at an angle to the leaf spring 19 and the short arm 99 extending away from the leaf spring into the corresponding slot 99. A contact tip |0| is secured to the outer end of the long arm 99 of each contact finger, as by welding or brazing, and the length of the long arm 99 of each contact finger is such that the contact tip |0| on each finger is adapted to be engaged by a corresponding contact tip 99 on the leaf spring 19 upon rotative movement of the inertia ring 5| relative to the tubular axle I2.

Each of the insulating blocks 19 has secured u thereto on the outer surface thereof a transverse- 0 ly extending strap |02, of insulating material, and screwed into the strap |02 are three so-called stop screws |03, as shown in Fig. 6, so located in spaced relation as to extend respectively into a corresponding slot 99 in the corresponding insulating,r block 19. Interposed between the short arm 99 on each contact finger and the insulating block 19 is a small coil spring |09 that yieldingly rocks the arm 99 and consequently the contact finger in a direction toward leaf spring 19. The stop screws |09 which`project into the slot 99 are enaged by the short arms 99 of the corresponding contact fingers to limit the movement of the contact fingers in the direction of the leaf spring 19 so that, normally, the contact tips I 0| on the con- 5 tact fingers are separated from the contact tips 99 on the leaf spring 19.

For a reason which will be hereinafter explained, the stop screws |09 for the contact fingers 9|, 92 and 99 are so adjusted that the contact 10 tips |9| on the three contact fingers are normally different distances away from the corresponding contact tips 99 on the leaf spring 19, the contact tip of the contact finger 9| being closest to the leaf spring, the contact tip of the contact finger 15 99 being farthest away from the spring, and the contact tip of the contact finger 92 being an intermediate distance away from the leaf spring.

In a similar manner, the contact fingers 9|a, 92a and 93a on the opposite side of the leaf 20 spring are normally positioned different distances away from the leaf spring by the corresponding adjusting screws |03.

It will thus be seen the arrangement of the contact fingers and the leaf spring 19 is such that 25 when the inertia ring 5| shifts in one direction rotatively with respect to the ring member 55 and tubular axle 2, the contact tips 99 on the leaf spring successively engage the contact tips |0I on the contact fingers 9|, 92 and 99 in succession as the displacement of the inertia ring from its normal position increases. In a similar manner, the contact tips 99 on the opposite side of the leaf spring successively engage the contact tips on the contact fingers 9|a, 92a and 93a in succes- 35 sion with increasing displacement of the inertia ring 5| out of its normal position with respect to the ring member 55 and tubular axle |2.

As seen in Figs. 2 and 6, an individual terminal strap or bolt |09 is provided for each of the con- 40 tact fingers and for the leaf spring. The terminal bolts |09 for the contact fingers are embedded in the insulating blocks 19, when molding the blocks, in such a manner that the inner end thereof is engaged by the biasing coil spring |04 for the 45 corresponding contact finger, the outer end of each terminal post being threaded to receive nuts for securing an electric wire thereto.

In the case of the leaf spring 19, the insulating blocks I9 are suitably formed so as to accommo- 50 date the corresponding terminal post |06 which is secured to the wide end of the leaf spring 19 as by riveting it thereto. (See Fig. 3.) The outer end of the terminal post |09 of the leaf spring 19 55 is threaded to receive nuts for securing an electric wire thereto.

, The specific arrangement of three contact fingers on each side of the leaf spring 18 is adapted for employment in connection with a brake con- 60 trol equipment of the type described and claimed in my prior Patent 2,132,959, or my copending application Serial No. 284,654, filed December 31, 1938. However, the number of contact fingers on each side of the leaf spring 19 may be varied or 65 there may be more contact fingers on one side of the leaf spring than on the other, if desired, depending upon the particular brake control equipment with which the rotary inertia device is employed. For example, in my copending applica- 70 tion Serial No. 248,653, filed December 3l, 1938,

the rotary inertia device may have only one contact finger on one side of the Ieafspring and four contact fingers on the opposite side.

In order to enable the installation of the two 75 insulating blocks 1I with leaf Spring 'Il secured in clamped relation therebetween, as a unit, into the opening 15 in the web of the inertia ring Il, a recess |69 is cut on the inner surface of the 5 rim 53 at a point between the knife edge lugs 96 for receiving the outer end of the leaf spring thereinto while the mechanism is being inserted transversely into the opening 15.

The bumper mechanism 11, previously referred l0 to, comprises a flanged yoke which straddles the hub 54 of the inertia ring and is secured, as by a plurality of screws ||2, to the ring member 55 (see Figs. 2 and 3).` Secured in suitable recesses formed inthe yoke HI, as by transversely extending pins ||3, are a pair of oppositely facing bumper pieces ||4 of yielding material such as rubber. Secured tothe opposite edges of the web 52 of the inertia ring 5| and extending in opposite directions into the opening 15 in the web are a pair of stop lugs ||5 that are adapted to be engaged by the corresponding bumper pieces ||4 on the yoke when the inertia ring 5| shifts rotatively relative to the ring member 55 and tubular axle |2 a distance slightly greater than that required to eilect engagement of the leaf spring 16 with the farthest removed contact finger I3 or 93a. The bumper mechanism 11 accordingly functions to limit the flexing of the leaf spring 1l to a degree insufficient to cause breaking thereof.

' In order to prevent as much as possible, the entry of dust, dirt or other foreign particles into the central opening 46 of the brake cylinder housing 45, which might interfere with the proper electrical contact between the contact .fingers and the leaf spring 16, a pair of sheet metal end covers or discs |2| are provided as shown in Figs. 1 and 8. 'I'he end covers |2| are of substantially the same diameter as the central opening 49 in the brake cylinder housing and one is located at each end of the opening 43 between the innermost rotative brake ring 38 and Ithe adjacent face of the brake cylinder housing 45, suitable openings |22 being provided therein through which the tie rods 33 connecting the radial flanges 29 of the sleeve members 26 extend. Each of the end covers |2| is also provided with a large central' opening |23 circular in form and having a slight clearance with respect to the outer surface of the tubular axle I2 which extends therethrough. Since the tie rods 33 extend through the end covers |2|, the end covers obviously rotate with the rotative brake rings of the disc brake device and the tubular f axle |2.

Each of the end covers i 2| is formed by two lsemi-circular portions adapted to meet along a common' diametrical edge. The two portions of each end cover may be secured together in any en suitable manner, as in the manner shown in Figs. 8 and 9, by providing a series of spaced tongues |24 along the diametrlcal edge of each half-portion and staggering the tongues |24 on one half-portion with respect to the tongues on e5 the other half-portion so as to interlock with each other.

The tie rods 33 are provided with suitable integrally formed collars |26 which are engaged by the end covers |2| to limit the inward movenient thereof along the rods 33 to a point in close clearance with the brake cylinder housing 45. The end covers are engaged by the adjacent rotative brake rings 39 and urged slidably along the tie rods into contact with the collars |26 u under the influence of the release springs for the rotative brake ring 39. When iluld underv pressure is supplied to the brake cylinders 49 in the brake cylinder housing, the rotative brake rings 36 are shifted along the tie rods 33 away from the end covers |2| so that the force of 5 the release spring of the rotative brake rings 39 urging the end covers |2| toward the brake cylinder housing is removed. However, in view of the close fit between the rods 33 and the openings |22 in the end covers, the end covers 10 are frictionally held in position notwithstanding the disengagement of the rotative brake rings 39 therefrom.

It will be apparent that since the contact switch mechanism 16 is secured to and rotated l5 with the tubular axle I2, some form of slip or collector ring arrangement is necessary -to establish the electrical connection between the con-- tact fingers of the switch mechanism and stationary parts of a brake control equipment with 20 which vthe rotary inertia device is associated. As shown in Fig. 10, a collector ring arrangement is accordingly provided, comprising four collector rings |3|, |32, |33 and |34 and a brush holder device |35 having a plurality of brushes |36, |31, 25 |38 and |39 adapted to engage the collector rings 3| to |34 respectively.

The collector rings |3| to |34 are secured in concentric relation to the tubular axle |2 in suitably insulated axially spacedrelation to each 30 other along the tubular axle I2 by a plurality of securing bolts 4| that screw into the radial flange 29 of the right-hand sleeve member 26 shown in Fig. 1. In order to facilitate assembly around the 'tubular axle l2, the collector rings v35 are split into two complementary half-portions. In order to insure true circular form for the collector rings, they are formed initially as integral vrings and the necessary circular openings through which the securing bolts |4| extend 40 bored therein prior to severance of the collector rings along a diametrical line. As seen in Fig. 12, each semi-circular half-portion of each collector ring is adapted to be secured by three bolts or screws |4|, one adjacent each of the 45 abutting ends of the two half-portions and one at an intermediate point therebetween.

As shown in Figs. 10 and 12, suitable metallic U-shaped connecting clips |44 are provided for connecting the two half-portions of each col- 50 lector ring. As will be evident, each clip |44 straddles its associated ring and engages the opposite sides of the ring, and is provided with suitable circular openings through which the securing bolts |4| extend. Electric connection 55 of wires to each of -the collector rings is made by soldering or otherwise securing a wire to the clip 44 of the corresponding ring.

Referring to Fig. 11, the brush device |35 com prises a metallic supporting frame |48 that hasl 60 l a rectangular opening |49 therein for receiving a block of insulating material |5| in which are rectangular openings |52 .for receiving the brushes |36 to |39. The metallic frame |49 is secured m insulated relation to a. bracket |54 65 by a pair of screws |55 and the bracket |54 is, in turn, attached by four suitable screws |56 to a pedestal base formed on the hub portion 22 of the adjacent truss member 2| of the rectangular supporting frame of the disc brake. A 70 cover member |59 of insulating material is secured to the metallic frame |48 by four securing bolts that screw into corresponding tapped holes |6| at the four corners of the metallic frame |48.

Suitable circular bores |62 are provided on the 75 inner face of the cover |63 for receiving coil springs |63 that act to urge the brushes |36 to each of the brushes |36 to |36 respectively. The

terminal post for each brush is suitably'embedded in the molded insulating cover |66 in such a manner that the inner end thereof enters the recesses receiving the biasing springs |63 to the brushes and is engaged thereby, the outer end of the terminal post being threaded to receive suitable nuts for securing wires thereto.

The bracket |54 supporting the brush device |36 is provided with anextension that has an opening |61 through which the wires connected to the brushes extend. As shown particularly in Figs, 10 and 1.2, the bracket |54 is also provided with two laterally extending channelshaped portions |66 extending in opposite directions from the opening |61 for receiving and supporting the wires connected to the terminal posts of the brushes, a suitable clip |69 and securing screw |10 therefor serving to hold the wires in place in the channel-shaped portions |66.

In order to protect the collector rings and the brush holder from dust, dirt and other foreign particles, a cover |12 of sheet metal is provided. As shown in Fig. 12, the cover |12 is formed as two cooperating portions adapted to be secured together by bolts |13 in surrounding relation to the collector ring and the brush holder, each portion of the cover |12 having a radially extending iiange that has a central opening conforming closely to and having clearance with respect to the brush holder bracket |54 and the hub 22 of truss member 2|. The portions of the cover |12 are secured to the truss member 2| by four bolts or screws |14, only two of which are visible in Fig. 12.

Referring to Fig. 7, the electrical connections between the contact fingers of the contact switch mechanism 16 as well as the leaf spring 16, and the collector rings |3| to '|34 are shown diagrammatically. Briefly, each corresponding contact finger on opposite sides of the leaf spring 16 of the contact switch mechanism 16 is connected to the same corresponding collector ring and the leaf spring 16 is connected individually to its own collector ring. Thus, the corresponding Contact fingers 9| and 9|a on opposite sides of the leaf spring 18 are both connected, as shown, to the same collector ring |33. In a similar manner, the corresponding contact fingers 92 and 92a are connected to the same collector ring |32, and the corresponding contact fingers 93 and 93a are connected to the collector ring |3|. Leaf spring 16 is connected to the collector ring |34. As a practical matter, there is an individual wire connecting each contact linger to its corresponding collector ring. The two wires from corresponding contact lingers on opposite sides of the leaf spring being connected to the same tie clip |44 of the corresponding collector ring.

Thus in Fig. l, there are seven wires leading from the switch mechanism 16 to the collector rings |3| to |35. It will be understood that the radial ilange 26 of the sleeve 26 surrounded by the collector ring is prdvided with suitable slotted openings Ill through which the wires connecting'the contactfingers and leaf spring of the contact switch mechanism 16 to the collector rings, extend.- A pair of clamping rings |63 are provided for holding the seven wires to the outside surface of the rtubular axle against the action of centrifugal force.

Operation I No attempt will be made herein to describe in detail the operation of the rotary inertia device in a brake control equipment because such operation will be understood by reference to my copending application Serial No. 248,654, above referred to. A brief description of suchvoperation of the rotary inertia device may be helpful, however.

Assuming, therefore, that an application of the brakes has been initiated and fluid under pressure supplied to the brake cylinders 46 of the disc brake device to cause the frictional engagement of the rotative and non-rotative brake rings thereof and a consequent rotative deceleration of the vehicle wheels 1|, the inertia ring tends to overrun the tubular axle I2 in one direction or the other depending upon the direction of rotation of the tubular axle. Assuming that the tubular axle l2 is rotating in a counterclockwise direction as seen in Fig. 2, the inertia ring 5| tends to shift rotatively relative to the tubular axle |2in a counterclockwise direction upon the rotative deceleration of the tubular axle and the connected vehicle wheels I. Obviously, the leaf spring 16 yieldingly resists the rotative displacement of the inertia ring 5| relative to the tubular axle I2 and the displacement oi' the inertia ring rotatively with respect to the tubular axle I2 is substantially in accordance with the rate of deceleration of the vehicle wheels.

As will be recalled from the previous description, contact fingers 9|, 92 and 63 on one side of the leaf spring and the contact iingers 9|a, 92a and 63a on the opposite side of the leaf spring of the switch mechanism 16 are normally adjusted by the adjusting stop screws |03 to require successively greater degrees of fiexing of the release spring 16 to effect the engagement of a corresponding contact tip 86 of the leaf spring 16 with the contact tip ||l| on the contact finger. In my copending application Serial No. 248,654, it is assumed that the engagement of the leaf spring 18 and contact fingers 9| and 9|a occurs at a rate of rotative deceleration of the vehicle wheels corresponding to a rate of retardation of the car or train of 4.4 miles per hour per second. Obviously, engagement of the leaf spring 16 with either of the contact fingers 9| and 9|a occurs upon the rotative deceleration or the rotative acceleration of the vehicle wheel depending upon which direction the inertia ring 5| shifts from its normal position. During any one application of the brakes, one of the contact lingers 9| and 9|a is engaged by the leaf spring in response to the deceleration of the vehicle wheel and the other is engaged in response to the rotative acceleration of the vehicle wheel.

In a similar manner, the adjustment of the contact fingers 92 and 92a is such that they are engaged by the leaf spring 16 when the rotative deceleration or acceleration of the vehicle wheel attains a rate corresponding to a rate of retardation or acceleration of the car or train .of 5.5 miles per hour per second.

In a similar manner also, the adjustment of the contact fingers 99 and 93a is such that they are engaged by the leaf spring 18 when the ve` hicle wheels rotatively decelerate or accelerate in excess of a rate corresponding to a rate of retardation or acceleration of the car or train of 7.7 miles per hour per second.

As will be understood from my copending apf plication Serial No. 248,654, electroresponsive devices controlled respectively by electrical circuits including the leaf spring 18 and the contact fingers 9i, 92, lla and 92a, may be provided for regulating and controlling the pressure in the brake cylinders so as to regulate the rate of retardation of the car or train to a substantially uniform rate somewhere between the values of 4.4 and 5.5 miles per hour per second.

The coefficient of adhesion between the vehicle wheels and the track rails is such that rates of rotative retardation of the vehicle wheels in' excess of a rate corresponding to a rate of retardation of the car or train of six miles per hour cannot be produced without exceeding the coefficient of adhesion vand causing the wheels to slip. The contact fingers 93 and 93a, being thus set so as to be engaged by the leaf spring 10 only upon a rotative rate of retardation of the vehicle wheels corresponding to a '7.7 miles per hour per second rate of retardation of the car or train, are effective in the event that the vehicle wheels begin to slip to setup certain control circuits, on which electroresponsive valve devices operate, for controlling the rapid release of the fluid under pressure from the brake cylinders of the disc brake associated with the vehicle wheels that begin to slip.

As will be evident from my copending application Serial No. 248,654, the engagement of the leaf spring 18 with the contact nger 93, assuming rotation of the vehicle wheels and tubular axle I2 in a counterclockwise direction as seen in Fig. 2, effects the instantaneous and rapid release of fluid under pressure from the brake cylinders 49 of the disc brake. When the slipping vehicle wheels cease to decelerate and begin to accelerate back toward a speed corresponding to car speed in response to the release of the brakes thereon, the inertia ring 5I tends to lag behind the vehicle wheels, and, since the vehicle wheels accelerate very rapidly back toward a speed corresponding to vehicle speed during the slipping interval, the consequent engagement of leaf spring 18 with the contact finger 93a is effected. The engagement of the leaf spring 18 with the contact finger 93a is effective to terminate the release of fluid under pressure from the brake cylinders 49 and initiate a controlled resupply of fluid under pressure thereto to effect reapplication of the brakes.

In my copending application Serial No. 248,654, a so-called direction coordinator of novel construction is provided so as to enable the contact fingers 93 and 93a to be connected in parallel relation, thus necessitating only one collector ring for the two contact fingers, instead of a separate collector ring for each contact finger.

Since the corresponding Contact fingers 9| and 9|a and the corresponding contact fingers 92 and 92a are `connected in parallel relation and adjusted to the same setting respectively, it will be apparent that the rotary inertia device functions to control the rate of retardation on the car or train so as to regulate it to a substantially uniform rate regardless of which direction the wheels of the cars rotate.

EMBonrunNT Snowm nw F1os. 13 no 16 that is mounted, in a manner presently to be described/for limited rotative movement relative tothe tubular axle I2 in concentric relation thereto. v

The inertia ring 25| is of a diameter somewhat smaller than that of the central opening in the brake cylinder housing 45 and a plurality of A angularly spaced recesses are formed or cut therein to provide the necessary clearance between the inertia ring and the tie rods 33 that extend through the central opening 4l of the brake cylinder housing 45 in parallel relation to the tubular axle |2 and connect the radialanges 29 of the sleeve members 26 shown in Fig. 1.

Just as in the case of the inertia ring -5l of the first described embodiment, the inertia ring is formed originally as an integral ring of true circular form and subsequently cut along a diametrically line into two similar half-portions. Prior to the separation of the inertia ring 25| into two portions, tie straps or plates 202 are clamped on opposite side surfaces of the inertia ring at the diametrically opposite points, in symmetrica] relation to the intended line of severance, and holes for receiving securing bolts 203 therefor are located and bored through the plates 202 and the ring 25|. The tie plates 202 are then removed and the ring 25| cut along the intended line of severance. It will thus be seen that when the two half-portions of the inertia ring 25| are assembled in concentric relation to the tubular axle and secured together by the tie plates 202 and bolts 203, the inertia ring 25| possesses a true circular form.

A sleeve member 205 is clamped in surrounding relation to the outer surface of the tubular axle I2 at a point within the projection of the side surfaces of the brake cylinder housing 45 thereon. The sleeve 205 is of split construction, be-

irig made up of two similar semi-circular halfportions which have cooperating lugs 206 thereon for receiving securing bolts 201. The wall of the sleeve 205 has a plurality of circular bores 208 extending radially therethrough and located at substantially equal angular distances apart around the periphery of the sleeve 205 at a point substantially mid-way between the opposite ends of the sleeve.

Prior to assembly of the sleeve 205 on the tubular axle, a tubular cage 209 is inserted through each of the bores 208, respectively, in a manner to extend radially outward from the axle i2, the cages 209 having a flange 2i| at the inner end thereof of larger diameter than that of the main portion of the cage which is received in a counterbore 2|2 of the bore 208 so as to permit the sleeve 205 to be clamped in close surrounding contact with the outer surface of the tubular axle i2. A coil spring 2|3 is contained within each of the cages 209 in interposed relation between the outer surface of the tubular axle I2 and a collar or flange 2|4 of a rod 2|5 that projects radially outward in slidable relation through the outer circular opening 2li in the cage 209,

the rod 2| 5 carries at the outer end thereof a pin 2I'l on which a pair of rollers 2I8 located respectively on opposite sides of the rod 2|5 are rotatably mounted.

The inertia ring 25| has a central opening 22| therein and the edge of the inertia ring 25| at the central opening is provided with a peripherally extending groove or recess 222 of sufficient width so that each pair of rollers 2|8 for each cage 209 is received therein.

When the inertia ring 25| is assembled in concentric relation around the tublar axle I2 for rotative movement on the rollers 2|8, the coil springs 2I3 biasing the rollers 2I8 radially outward are slightly compressed so as to provide a slight clearance between the flange 2I4 on the roller-carrying rod 2|5 and the outer inwardly extending flange of the cages 209. The coll springs 2I3 are relatively heavy and the various springs in the several cages 209 exert substantially equal outward forces on the rollers 2I8 so that the inertia ring 25| is normally positioned in true concentric relation to the tubular axle I2.

The springs 2I3 serve as a cushioning means in somewhat the same manner as the rubber cushioning ring 56 of the first described embodiment, that is, they function to ease the mechanical stresses on the parts of the rotary inertia device resulting from rod shock on the vehicle wheels and the tubular axle I2 connecting the wheels.

The inertia ring 25| is adapted to be rotatively driven by rotation of the tubular axle I2 through a resilient connection that includes a pair of coil springs 225, a pair of bell-crank levers 226 and two additional pairs of levers, 221 and 228 respectively. The bell-crank levers 226 are disposed respectively on opposite sides of the inertia ring 25| and pivoted at the fulcrum thereof on a pin or screw 23| screwed into the ring 25|. Each of the bell-crank levers 226 has a long arm 232 and a short arm 233. The coil springs 225 are suitably supported in interposed relation between the outer end of the short arm 233 of the respective bell-crank levers 226 and a corresponding angle bracket 234 secured `as by screws 235 to the side surface of the inertia ring 25|.

The other pairs of levers 221 and 228 are similarly arranged so that one of the levers of each pair is on one side of the inertia ring and the other lever of the same pair is on the opposite side of the inertia ring. The levers 221 and 228 on the same side of the inertia ring are pivotally connected at one end thereof as by a pin 231, the opposite end of the lever 221 being pivotally connected to the outer end of the long arm 232 of the bell-crank lever 226 on the same side of the inertia ring as by a pin 238, and the opposite end of the lever 228 being pivoted on a pin or screw 229 screwed into the inertia ring. The levers 226, 221 and 228 are preferably notched at the end thereof to provide lap joints so that the three levers 226, 221 and 228 on each side of the inertia ring are in the same plane of movement perpendicular to the tubular axle I2.

The distance between the fulcrum screw 23| and the pin 238 at the outer end of the long arm of the bell-crank lever 226 is substantially equal to the distance between the pivot screw 239 and the pin 231 of the lever 228. Also, the distance .between the pins 231 and 238 at opposite ends of the lever 221 is substantially equal to the distance between the fulcrum screw 23| of the lever 226 and the pivot screw 239 of the lever 226. Accordingly, with the inertia ring 25| stationary,

the coil springs 225 acting on the short arms 233 on the two bell-crank levers 223, position the levers 228, 221 and 228 on each side of the inertia ring 25| so that the levers 226 and 228 are substantially parallel and the lever 221 is substantially perpendicular to the long arm of lever 232 of lever 236 and to lever 228.

Mounted substantially mid-way between the fulcrum point of each bell-crank lever and the outer end of its long arm 232, as on a pin 24| fixed to the lever, is a roller 242, the rollers 242 being on the inside of each of the levers and extending toward each other within the central opening 22| of the inertia ring.

Suitably secured to the outer surface of the sleeve `205, as by screws 243, are a pair of socalled yoke straps 244. Each yoke strap 244 extends radially outwardly from the sleeve 205 and is of such contour as to form two converging cam surfaces 245 on the inside edge or surface thereof with which the roller 242 of a corresponding bell-crank lever 226 is associated. Each yoke strap 244 is normally symmetrically disposed with respect to its associated roller 242 on the bell-crank lever 246 and the two cam surfaces 245 on the yoke strap converge radially outwardly to an apex, in which the roller 242 is normally positioned.

The coil springs 225 are so designed and are of such strength as to maintain the rollers 242 in the apex between the two converging cam surfaces 245 on the associated yoke strap 244 as long as the tubular axle I2 and inertia ring 25| rotate at substantially the same speed. When the brakes are applied to the tubular axle I2 and `it consequently tends to rotate at a slower speed than the inertia ring 25|, the rollers 242 roll up one or the other of the inclined cam surfaces 245, depending upon the direction of rotation of the axle I2, so that the bell-crank lever 226 is pivoted on its fulcrum screw 23| in a counterclockwise direction, as seen in Fig. 13, against the yielding resisting force of the coil springs 225. Thus, assuming that the tubular axle I2 is decelerated while rotating in a clockwise direction, the rollers 242 roll up the right-hand cam surface 245 and the bell-crank lever 226 is rocked in a counter-clockwise direction. 'I'he springs 225 yield in a manner to cause the rotative displacement of the inertia ring 25| forwardly of its normal position with respect to tubular axle I2 to correspond substantially to the rate of rotative deceleration of the tubular axle I2 and the connected vehicle wheels I I.

Conversely, if the vehicle wheels and the connecting tubular axle I2 are accelerated, the cooperative action of one or the other of the cam surfaces 245 with the associated rollers 242, also causes the :bell-crank levers 226 to be pivoted in a counter-clockwise direction to compress the springs 225. Thus, assuming that the tubular axle I2 is accelerated in a clockwise direction, as seen in Fig. 13, the left-hand cam surface 245 on the yoke strap 244 cooperates with the roller 242 to cause counter-clockwise pivotal movement of the bell-crank lever 226. Just as in the case of the deceleration of the tubular axle I2, so for acceleration of the Vehicle wheels, the coil springs 225 yieldingly permits rotative displacement of the inertia ring 25| backwardly of its normal position with respect to the tubular axle I 2 an amount which corresponds substantially to the rate of rotative acceleration of the vehicle wheels and tubular axle I2.

,It will be apparent that the two pairs of 

